376 DISEASES OF THE FEET. 



wall, and is usually small and insignificant at first ; but it 

 gradually extends downwards and inwards, and when it has 

 penetrated through the horny structures, lameness becomes 

 apparent ; inflammation is set up, both in the laminae and with- 

 in the skin above the fissure ; the part is very painful, and the 

 lips of the wound, at its upper part, gape as the tissues swell. 



In some rare instances, however, lameness may be present 

 before the appearance of the fissure. When such is the case, we 

 may reasonably conclude that the fissure commences on the 

 inner part of the wall, being the converse to the general rule. 



Wlien the animal is made to move, the crack is seen to close 

 every time the foot is put to the ground, and to open again 

 when the weight is removed from it; during this closure the 

 borders of the crack grasp some of the sensitive and swollen 

 tissues, causing most excruciating pain and sometimes haemorr- 

 hage. Sand and dirt insinuate themselves into the wound, act 

 as irritants, give rise to the suppurative action, and in some 

 instances to a high degree of irritative fever. It is very painful 

 to witness a horse, especially a heavy cart-horse, attempting to 

 walk with sand-crack at the toe. He keeps the foot elevated 

 from the ground as long as possible ; puts down the heel first 

 very carefully ; and when the toe is forced to touch the ground, 

 he immediately lifts the foot with a sudden catch, the pain 

 being often so poignant as to cause him to groan. 



A sand-crack may occur through the bars, but it is very rare. 



Treatment. — If inflamed, remove aU sources of irritation, and 

 pare the edges of the crack if they press upon the tissues ; in 

 fact, " bottom the crack" and allow the escape of pus, dirt, &c. ; 

 remove the shoe, and give purgatives ; order fomentations and 

 rest. A fungous growth is generally seen fiUing the fissure ; this 

 is the result of the inflammation, depends upon it, and disap- 

 pears upon its subsidence. It must not be destroyed by caustic, 

 for the application will add to the irritation. When the inflam- 

 mation and pain have subsided, place a bar shoe (thin heeled, 

 with side clasps, if the crack be in the toe) on the foot, allow sole 

 as well as frog pressure, but remove the pressure from that part of 

 the foot immediately below the crack ; pare away the upper part 

 of the crack from its coronary attachment, and let no direct 

 communication remain between the fissured horn and the sub- 

 stance from which new horn is to grow, or the crack wiU be 



